Skin color ranges from pinkish white to very dark brown with an infinite shadings of color in between. There is no simple classification unless you want to use the traditional but inaccurate: "white, yellow, red, brown and black"
You can say "She is white" or "She is black" (although many prefer "African-American")
but you would not say "she is yellow, brown or red,
instead you would say, "She is oriental, Latina or Hispanic or Native American.